Chapter 4. CPU Operation152 PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual GFK-2222AD4.5.2 STOP-to-RUN Mode TransitionThe CPU performs the following operations on Stop-to-Run transition:▪ Validation of sweep mode and program scheduling mode selections▪ Validation of references used by programs with the actual configured sizes▪ Re-initialization of data areas for external blocks and standalone C programs▪ Clearing of non-retentive memory4.5.3 RUN/STOP Switch OperationThe RUN/STOP Switch is a 3-position switch which operates as follows:Switch Position CPU and Sweep Mode Memory ProtectionRUN I/O orRUN I/O EnableThe CPU runs with I/O sweep enabled. User program memory is read only.RUN orRUN Output DisableThe CPU runs with outputs disabled. User program memory is read only.STOP The CPU is not allowed to go into RUN Mode. User program memory can be written.The RUN/STOP Switch can be disabled in the programming software HWC. The memory protectionfunction of the switch can be disabled separately in HWC. The RUN/STOP Switch is enabled by default.The memory protection functionality is disabled by default.The Read Switch Position (Switch_Pos) function allows the logic to read the current position of theRUN/STOP Switch, as well as the mode for which the switch is configured. For details, refer toPACSystems RX7i, RX3i and RSTi-EP CPU Programmer’s Reference Manual, GFK-2950 Chapter 4.
